{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-68083", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-30T09:28:09.367Z", "datePublished": "2026-08-10T11:41:47.153Z", "dateUpdated": "2026-10-30T12:28:02.157Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-30T12:28:02.157Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix path resolution in ksmbd_vfs_kern_path_create\n\nThe SMB2 open lookup is rooted at the share with LOOKUP_BENEATH, but the\ncreate/mkdir/hardlink sink is not: ksmbd_vfs_kern_path_create() builds an\nabsolute path with convert_to_unix_name() and resolves it from AT_FDCWD\nvia start_creating_path(), so a \"..\" component is walked from the real\nfilesystem root and escapes the export.\n\nAn authenticated client races a missing path component so the rooted open\nlookup returns -ENOENT (taking the create branch) while the same component\nis present (a directory) when the create walk runs; the create then\nresolves \"..\" out of the share.\n\nRoot the create walk at the share like the lookup and rename paths already\nare: resolve the parent with vfs_path_parent_lookup(..., LOOKUP_BENEATH,\n&share_conf->vfs_path) and create the final component with\nstart_creating_noperm(). convert_to_unix_name() then has no callers and is\nremoved." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H", "baseScore": 9.1, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - ksmbd is the in-kernel SMB server on TCP/445; the flaw is reached from remote SMB2_CREATE (and SMB2_SET_INFO hardlink) requests processed in ksmbd_conn_handler_loop() through smb2_open()/smb2_create_link() into ksmbd_vfs_kern_path_create().\nAC:L - Exploitation requires a TOCTOU race, but the attacker controls both sides by issuing concurrent SMB2_CREATE and directory-creation requests over one or more connections, so success does not depend on conditions outside attacker influence.\nPR:N - SMB2_CREATE requires a valid session, tree connect, and writable share, but ksmbd supports guest/anonymous sessions on writable exports; per kernel CNA precedent, export write access alone is not elevated privilege.\nUI:N - No victim interaction is required; the attacker sends crafted SMB2 protocol requests directly to a reachable ksmbd service without needing another user to mount shares or open files.\nS:U - Impact is confined to the host kernel filesystem namespace managed by ksmbd; escaping an SMB export is not a VM, IOMMU, or separate security-authority boundary crossing.\nC:N - This is a path-resolution logic flaw with no memory corruption, out-of-bounds access, or demonstrated arbitrary read of host files outside the export; impact is unauthorized creation/linking, not information disclosure.\nI:H - ksmbd_vfs_kern_path_create() resolves attacker paths from AT_FDCWD without LOOKUP_BENEATH, letting authenticated clients create files, directories, or hardlinks outside the exported share using the server's filesystem credentials.\nA:H - Repeated successful escaped creates/mkdirs outside the export can exhaust root-filesystem inodes or storage (especially tmpfs/world-writable targets), causing system-wide service unavailability on affected NAS/cloud hosts." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/smb/server/misc.c", "fs/smb/server/misc.h", "fs/smb/server/vfs.c" ], "versions": [ { "version": "265fd1991c1db85fbabaad4946ca0e63e2ae688d", "lessThan": "f1f53dc95edfb3d2072e5e8cd8eb9a2fe7d7f2d0", "status": "affected", "versionType": "git" }, { "version": "265fd1991c1db85fbabaad4946ca0e63e2ae688d", "lessThan": "a2516be69048856e2a49a51e00975dc59431f95c", "status": "affected", "versionType": "git" }, { "version": "265fd1991c1db85fbabaad4946ca0e63e2ae688d", "lessThan": "489d1ded01425c0fb33418172c0e4e588467526b", "status": "affected", "versionType": "git" }, { "version": "265fd1991c1db85fbabaad4946ca0e63e2ae688d", "lessThan": "c7c884a1305aa4540eb7942a50bd356b34120e1f", "status": "affected", "versionType": "git" }, { "version": "265fd1991c1db85fbabaad4946ca0e63e2ae688d", "lessThan": "98185b3025beeae92d1fe700d5db26b9ac4bf025", "status": "affected", "versionType": "git" }, { "version": "265fd1991c1db85fbabaad4946ca0e63e2ae688d", "lessThan": "1c8951963d8ed357f70f59e0ad4ddce2199d2016", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/smb/server/misc.c", "fs/smb/server/misc.h", "fs/smb/server/vfs.c" ], "versions": [ { "version": "5.15", "status": "affected" }, { "version": "0", "lessThan": "5.15", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.191", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.1.191" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.6.160" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.12.97" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/f1f53dc95edfb3d2072e5e8cd8eb9a2fe7d7f2d0" }, { "url": "https://git.kernel.org/stable/c/a2516be69048856e2a49a51e00975dc59431f95c" }, { "url": "https://git.kernel.org/stable/c/489d1ded01425c0fb33418172c0e4e588467526b" }, { "url": "https://git.kernel.org/stable/c/c7c884a1305aa4540eb7942a50bd356b34120e1f" }, { "url": "https://git.kernel.org/stable/c/98185b3025beeae92d1fe700d5db26b9ac4bf025" }, { "url": "https://git.kernel.org/stable/c/1c8951963d8ed357f70f59e0ad4ddce2199d2016" } ], "title": "ksmbd: fix path resolution in ksmbd_vfs_kern_path_create", "x_generator": { "engine": "bippy-1.2.0" } } } }